Interrupter for automatic telephone or other switches.



No. 831,875. A PATENTBD SEPT. 25, 1906. A. E. KEITH. INTERRUPTER FOR AUTOMATIC TELEPHONE OR OTHER SWITCHES,

APPLICATION FILED 1133.17. 1905.

2 SHEETS-SHEET 1. a

i n i PATENTED SEPT. 25, 1906.

A. E. KEITH. INTERRUPTER FOR AUTOMATIC TELEPHONE OR OTHER SWITCHES.

APPLICATION FILED FEB.17.19OG.

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L I r o\\\\\\\\ WI UNITED STATES PATENT ostrich.

ALEXANDER E. KEITH, OF CHICAGO, ILLINOIS, ASSlGNOl-l TO JLlYi TEdATIF ELECTRIC COMPANY, OF CHICAGO, ILLINOlS.

lNTERRUPTER FOR AUTOMATIC TELEPHONE OR OTHER SWlTfJHES.

Specification of Letters Patent.

Patented Sept. 25, 1906.

Applloetinn filed February 1'7, 1906. Burial No. 246.126.

To all whom it may concern:

Be it known that I, ALEXANDER E. KEITH, a citizen of the United States of America, and

a resident of Chicago, Cook county, Illinois,

have invented a certain new and useful Improvement in Interrupters for Automatic elephone or other Switches, of which the following is a specification.

My invention relates to automatic telephone apparatus of that particular character in which automatic stepy-step switches are employed; and it relates more particularly to the so-called selector-switchesthat is to say, the switches which respond to elecirical lmpulses representing the first or sec ond digits of the number called-and in an apparatus of this character it is desirable that t e rotatablaand endwise-movable switchshaft be combined with means whereby. it will move endwise the desired distance and then rotate automatically until an idle trunk-- line is found and connection made therewith.

Generally stated, the object of my invention is the provision of an improved and highly effective arrangement for insurin an automatic step-by-step rotary motion 0 the switch-shaft of an automatic switch until an idle trunk-line or other connection is found and the desired connection established therewith.

A special object is the provision'of an improved construction and arrangement wherethe magnet or magnets employed for operating the switch-shaft in its step-by-step rotar'y movements also effect an intermittent olpenin and closing action of the circuit t iroug which current is supplied for energizing the said magnet or magnets and wherehvthe said magnet or ma nets are al tornnte y energized and denerggzed and the stephy-step mechanism there y o erated for the pur ass of rotating the switc -shaft until an .id 0 trunk-line is found and until the said energizing-circuit is automatically opened by the arrival of the-switch-shaft at a osition where connection is made with the liank contacts corresponding to the idle trunk-line.

Another object is to provide an improved construction and arrangement whereby cer tain apparu'us heretofore considered necessary and heretofore employed ior producing a vibratory or intermittent current in the circuit in which the said magnets or magnet are included may be dispensed with.

A further object is to provide an improved trunk-selecting switch mechanism.

Anothero b ect is to rovide an improved form of inteirpptertli at is to say, an arrangement whereby an electromagnet may automaticallydp circuit, and thus maintain a rapid vibration of its armature is long as the continuity of the circuit is pres ved at all of the points.

It is also an ob ect, of course, to provide certain details and features of improvement tending to increasexthe general efficiencyand serviceability of the means for automatically interrupting the current cmployedfor energizing the magnet or magnets which operate the step by-step mechanism in an automatic switch for use preferably in an automatic telephone system of this particular character. V

To the foregoing and other useful ends my invention consists in matters hereinafter set forth and claimed.

In the accompanying drawings, Figure l is aside elevation of that portion of an automatic switch-in this case a so-called selector-to whichmy invention relates. Fig. 2 is aplan of the mechanism shown in Fig. I. Fig. 3 is a dis am of the circuits involved in my improve interrupter for automatic switches. Figs. 4, 5, 6, 7, ends are fragmentary detail views showing a different positions of the switch-springs and the interrupter-arm for alternately opening and closing the circuit in which the magnetsin this case the am called rotary magnetsof the automatic switch are included. F 9 is a die ammaticfip ers ectivo view 0 a so-called ridging st selectorprovided with my improved means for automatically maintaining the step-b -step rotary motion of the shaft until an id e trunk-line is found.

As illustrated in Figs. 1 and 2 only a portion of the frame A is shown, together with only a portion of the rotary and cndwisemovable switch-shaf t B, the latter being supported in suitable hearings in any known or approved manner. The so-called rotary magnets-(J are mounted in the frame in any suit able mariner and provided vii-h a pivoted or swinging armature I). As shown, this armature has a. forwardly-cxtcnding arm d,

rod

1%}3011 which is pivotall mounted a pawl d. his pawl is controlle by a s ring (1, connected between the upper em of the awl and a lug on the arm (1. Stationary guir es (l and d cause the pawl when the said armature is vibrated to alternately engage and disenga e the toothed ratchet-hub b on the said switch-shaft. Spring means (1 of any suitable character are provided for holding the armature normally away from the magnets and in such position as to keep the pawl d normally out of engagement with the said ratchet-hub. Said armature is also rovided with a horizontally-projecting arm i", which may be of insulation and which is adapted to vibrate in unison with the armature.

bracket-arm E is also secured to the frame of the switch and is provided with switch springs e, e, and e. The springs e and e are normally in en agement with each other,- while the piece 0 insulation e, secured to the spring e, tends at all times to Prevent contact between the springs e and e. The ends of said springs are formed as shown in Figs. 4 to 8, inclusive, while the adjacent end portion of the interrupter-arm d is provided with a lateral projection d. When the armature is attracted, the projection d first engages the end portion of the spring e, as shown in Fig. 5, and then slips off sa1dportion and en ages the upper portion of the s )ring e, as s own in Fig. 4, it eing observed t at the spring W has a straight end portion lying between the laterally-projecting end portions of the other two springs. The movement of the armature continuing, the interrupter-arm bears upon the spring e sulii- 'ciently to take the spring e entirely out of contact with the spring e. When the armature is again released, theend'of the interrupter-arm (1 passes out from the end portions of the springs e and .e as shown in Fig. 6, thereby keeping the springs e and 6 out of engagement until the armature is completely restore to its normal osition. It will be understood, of course, t at each time the armature is attracted the awl d engages the ratchet-hub b, and there y rotates the shaft B one ste that is to say, one step in the direction 0 its rotation.

Referring to Fig. 3, which shows a simple form of the apparatus, it will be seen that the main battery is included in a grounded circuit and connected in series with the rotar magnets (J, and in this same circuit, which is normally open, the sprin s e and e are included. A pair of normaTl open relaycontacts 1 and 2 are also inclur ed in this circuit, said contacts being operated by the armature 3 of the relay-magnet 4. One terminal of this relay-magnet can be connected with the said battery, as shown, while the other terminal can be connected with other ap aratus and arranged in circuitwith means or closing the circuit of said relay. One pole of the said battery is grounded at 5, and the other end of the circuit is grounded at 6, thus iving a normally open grounded circuit inc uding a batterv, two normally closed contacts, two normally separated contacts, and the two rotary magnets. Now, assuming that in the operation of the switch the relay-magnet 4 is energized, the circuit of the magnet (J is thereby closed and the armature 1) attracted. This relay 4 can be any suitable relay or magnet; but in practice. it has often been found desirable and practicable to employ the socalled private: magnet of a selector for opening and closingthe contacts 1 and 2 and for keeping the normally open switch- )oints in the circuit of the relay-ma net closer until an idle trunk-line.is found. hen the armature D is attracted, it breaks the'contact normally existing between the springs e and c and thereby interrupts the flow of current in the circuit closed by the energizing of the relay 4. This of course causes thema nets 0 to release the armaturc-immediately a ter the forward st'roke of the latterhas caused the ppwl d to rotate the switch-shaft one step.

ponits release the projection d, carried by the interrupter-arm d, passes between the end portions of the springs e and e, and thereby, as previously stated, prevents a reengagement of the spring 6* with sprin e until after the armature has been allowed to regain its normal position, and it will be remembered that suitable spring means are employed for restoringsaid amature to its normal position. In this way the armature l) is alternately attracted and released, the armature being equipped, so to s eak, with means for alternately opening an closing the circuit of the ma met or magnets by which it is operated. in other words, the energizing of the so-called rotary magnets (J sets in motion the part or means by which the continuity of the energi zingcircuit is broken or interrupted and with the result, of course, that the armature. is instanti released, and this alternate make-and-breah action in the circuit of the magnet C will continue as long as the magnet 4 remains energized. As previously stated, this magnet 4 may be the so'callcd private magnet of a first-or second selector and in the operation of obtaining connection )etwccn two subscribers lines remains energized until the switclrshaftB rotates to a position calculated to establish connection with an idle trunk-line. In other words, and through the medium of any suitable, known, or approved arrangement, the magnet 4 can be so connected that it will remain ener ized while the wipers or arms of the switchraft are passing over bus contacts and will only become deenergiaer when the said wipers or switcharms find a set of bank-contacts correspondin, to an idle trunk-line.

By the foregoing arrangement I have made it possible to dispense with certain "intermittent current to the rotor for the purpose described and to matermll;

" stroke and to the further fact irot the circuit is even then not broken until the springs fly more or lessobjoctionublc apparatus hereto 1 fore employed for furnishing a vibratory or y magnets amplify am improve the operation of a selective switching apparatus otthis partieular character.

With the arrangement shown it is obvious that the stop (1 is something more than a mere.guide-that is to say, it not only guides the awl d into engagement with the ratchetteet on the shaft, but it also cooperates with said pawl in looking the shaft against any movement be end the, point necessary for completingeac stepoi t hcstep-by-step rotary motion. n other w0rds,-the pawl d engages the face or shortsurface of a tooth each time the in ct is energized and in so doing gives the she 1; one rotary step. Each step is, however, limited by the eng emen't of the pawl with the stop or guide :5, in smueh as such engagement crowds the pail firmly against the book or beveled surface of the next tooth. Consequently even the momentum of theshaft when thus propelled in a rotary manner is not sufiieient'to carry it by the point which marks the completion of each rotarv stepthat is, the point where the pawl becomes operative to positively interrupt each step of the mechanical step-bystep motion produced by the alternate energizingland deener izing of the magnet C. Furt ermore, it W1 1 be seen that the magnet-operated circuit-breaking means, comprising the arm d and the springs e, e, and e, is adapted and timed in its operation to each time maintain the continuit of the circuit until after the armature reaches the limit of its propulsive stroke, or, more broadly speaking, until after each step of the motion is completed. In this we the shaft is positively propelled for the ful extent of each step of its motion, no'part of such movement being dependent upon the momentum of the shaft, and consequently the shaft is always certain of being given the desired or necessary extent of movement before the circuit is opened or before the magnetic force ofthe magnet ceases. This action is of course assisted, so to speak, by the residual magnetism of the magnet, so that the positive interruption of the mechanical motion has a slight lead over the cessation of the magnetic force, thus insuring the positive and powerful propelling action throughout the entire range of movement necessary for completing each step of the step-by-step rotary motion of the shaft. l This is due, it will be seen, to the fact that the end of the arm (1 slips off from the end of the spring 0 at the instant that the ari'uature reaches t e limit of it's forward or propulsive back toward their normal pos t-dons and not until the spring e' strikes the end of the arm d, thus interrupting the movement of the three springs and permitting, the spring, c. to continue its movement, and thus move out of contact with the spring e. In other words, the end of the urmd" is separated from the spring e by the thickness of the end portion of the spring 0 during the propulsive stroke of the armature, thus permitting the mechanical motion to cease just prior to the o ening of the circuit, for the disengagement o the arm d from the spring e takes place practicall at the instant the armature reaches tic limit of its propulsive stroke, thus leaving the springs c and c in contact for the fraction of a second after the motion of the shaft is positively interrupted. In a. similar manner the end ofthe arm d in regaining-its normal position does not become disengaged fror the end of the spring 2 until the armature practically reaches the limit of its stroke away from the magnet, thus insuring a separation of the sprin s e and e for the fraction of s. second after t e armature and the pawl d reach their normal positions. In other words, the circuit-breaker is of such character and is so timed in its operation that the necessary condition, of the circuit is maintained until after each step of the rotarystepby-step motion is completed, and it is also adapted and timed in its operation to preserve the necessary condition of the circuit until after the armature is restored to its normal position.

In Fig. 9 the selector thus dialfi'ammaticallyillustrated is of a'welhknown type. In this diagram the switch-shaft B is shown rovided with the usual vertical and rotary in wipers 6 and b and with the well-known private wiper b. ,The said line-wipers cooperate with the bank of line-terminals l) in cstablishing any one of a number of possible connections, it being understood that each terminal consists of two contacts and is con- .nected with a trunk-line running to' some other point. These terminals are multiplied with corresponding terminals of all other solectors having terminals corresponding to the trunk-lines running to the selector shown in Fig. 9. Also the private-bank" contacts b are multiplied with the corresponding rivetebank contacts of all selecto 5 having ineterminals corresponding to 0 connected with the trunk-lines running to t terminals 1). The selector thus illustrated is rther identified by the usual and wellknown vertical magnet F, the release-magnet G, the side switch H, and the double locking-dog I, together with the ratchet-pawlsf and d, the re ease-lining, and the side-switch arms or wi ers 'l, 7-, 8, 9, and 10. These parts, as well as the other parts and devices indicated in thedrawings, arr: all familiar elements of a selector of this type and will require no further description.

As previously stated, the private magnet 4 controls the switch-contacts l and 2 through the medium of the usual side switch H. these contacts being closed together when the side switch is moved to second position. hen the rotary magnet (l is thus energized by the closing of a local circuit, its armature-finger 11 operates the private-ma net armature 25, thus putting the side switch in condition to move to third position as soon as the armature 3 is released. Suppose, however, that the lirst terminal engaged by the line-wipers is connected with a. trunk-line already in use, whereby the eorresponr ling private-bank contact engaged by the private wi )Ol' If has a guarding potential by reason 0' its connection to ground through some other switch. In such case thecircuitimmediately established from the grounded pole of the battery F through ground and through the privatebank contact, through the private wiper I),.

through the switch-arm H and the contact 1 2, through the private magnet 4 and the con ductors 13 and 14 to the non-grounded pole of the battery energizes the said private magnet. In this way the guarding potential at a busy private-bank contact is utilized in energizing the. private magnet, thus causing the latter to retain its armature 3 in its attractedposition. This of course preveuts the restoration of the armature 3 when the rotary magnet C is dei'mergized, and thereby prevents the shifting of the side switch from second to third position, and this energization of the private magnet, and the consequent retention of the side switch in its second position. is maintained as long as the private wiper If continues to encounter the privatebank contacts supplied witlrgnarding potential and until the wipers arrive at a osition corresponding to a trunk-line \vhic l is not busy. As soon as this happens the circuit through the private magnet is broken and the armature 3 18 released and allowed to .ell'eet a shifting of the side switchfrom second to third position. As soon as the side switch shifts to third position the incoming line conductors 15 and 16 are connected with the outgoing trunk-linc conductors 17 and 18 through the medium of the side-switch arms or wipers 9 and 10 and through the medium of the shaft-wipers b and IF.

In Fig. 9 the circuit-breaker is shown in a simplified form and in a manner similar to that in which it is shown in Fig. 3. It will be understood, however, that in actual )ractice the construction is preferably oi the form shown in the other figures of the drawings, inasmuch as it is desirable to insure a full stroke of the armature in both directions,

and, as stated, this is accomplished by so timing the operation of the circuit-breaker that either condition of the circuit is not changed or reversed until after the armature has reached the limit of its stroke in either direction, and this is particularly desirable with respect to the forward or propulsive stroke of the armature, inasmuch as the switch-shaft B is always subject to the retracting influence of the coil-spring 19. Consequently the construction is preferably such that the tension of this retracting-s ring is positively opposed by the magnetic orce of the rotary magnet until after the shaft has completed each rotary step, thus making it impossible for the double-locking dog I to fai to catch the shaft and hold it exactly in the right position. In'other words, should the magnetic force of the rotary magnet cease or fail just before the shaft reaches the desired position there would be nothing to prevent thespring from immediately giving the shaft a slight back rotation, and there would even be more or less danger of this uncertainty of action with the parts adjusted to break the circuit at the very instant that the rotary motion is positively interrupted. Consequently and as explained the continuity of the circuit is preferably main tained for the fraction of a second, at least, after the rotary motion of the shaft is positively interrupted or stopped, and with such provision I preclude or greatly reduce all danger of uncertainty of action on the part of the autmua-tic step-by-stcp rotary motion of the shaft. This adjustment of the inter rupter-springs may be modified in each individual switch in order that the best and most efticient operation of the switch may result. In some switches it may be found that an adjustment which breaks the circuit of the rotary magnet at an appreciable time before the rotary armature strikes the polepieces produces best results; but some switches require a more close adjustment, and my improved interrupting-machine affords opportunity for such ad ustment.

As previously stated, the )rivate magnet will remain energized while t 10 shaft-wi ers are passing over busy contacts and unti an idle or non-busy trunk-line is found. This is due to the fact, it will be seen, that the private contacts in the private bank and the trunk-line terminals in the. line-bank are arranged so close together in each and every level of the said banks that both the line and the private wipers engage one contact or terminal before breaking contact with another. In other words, the private wiper slides readil from one contact to another without ever icing completely out of engagement with the same, whereby if the first five contacts in any level-are busy the private magnot will remain constantly energized until the private wiper is completely disengaged from the fifth contact. The energizing of said private magnet, as well as the ener izing of the vertical and rotary magnets an also the release-magnet, is controlled by. the usual so-called vertical" and rotary linerrela s J and K, which latter are bridged acrosst e line conductors and 16 with the middle point of the bridge bctwm-u the two relu s rumioct -to the non-grounded polo'of tic lm wry ,nrough the nicdimnof the normally closed contacts of tho bridgr-vut-oil relay L. When the selector is in use, the guarding potential is furnished from the grounded pole of the battery through the contacts 72. and 8,

rough the conductor h, and through the rivato wiper If to tlnprivstcdmnk contact which is engaged by tho said private wiper and thcncc to all multiples of such contact in other selectors or Switulu-s.

It will be seen, therefore, that my invention broadly contemplates an intcrruptcr adopted and timcd in its opcratiou to maintain the ncc- 'sury condition of the nmgnct-rircuituntil tor the armature reaches the limit of its propulsive stroke-that is, until after the arzo mature has been moved the desired distance in one direction. Also it broadly contemplates on interrupter which will maintain the necessary condition of the circuit until after the armature reaches the lirnit of its movement in the opposite direction. More spociiically considered, it contemplates an inter dupter which will maintain the continuity of the circuit until after the mechanical motion is positively interrupted.

o ciiically considercd,'it contemplates an interrupter adapted and timed in its operation to keep the magnet circuit open until after the armature machcs its position of rest. ,Again, as herein shown and described, my invention broadly contemplates the use of a. select-oructuutmg" magnet for opening and closing its own circuit so as to automatically innintain the ste t-step actuation of the ma chino until an ii l'c-trunk-linc is found. Also,

and more specificully considered, my invention contemplates the combination of a telelhone selector-actuating magnet with means or positively hitcrmptiug the mechanical motion and with an interrupter operated by"- said ma not in such manner as to kec the circuit closed until after the mechanic motion is positively interrupted. In other words, my improved interrupter and means i or automatically selecting an idloct runk-line is broadly naw,so far as I am aware, and

' the specific character of interrupts! by itself is also of course 'broudly' new. it is also broadly new, so far as l amfnware, to operatively combine a. selector-actuating magnet.

or other tclephone-switch-opemting magnet with means of any suitable character where: yr itmay automatically opcnand close its out ofbusy contacts and until an idle trunko is found. Furthermore, my invention "onte n lates a trunk-selecting switch. mechnnism aving provisions for automatically andintcrmittently interruptingits operato n circuit wliilo thema-chine is passing in I Also, more spestep-byste actuation of the sclecti mechanism unti an idle trunk-lino is foun' By my invention each trunk-selecting switch mechanism is complete in itself and s self-contained in this respect-namely, that it contains the means for producing the vibratory current essential to an automuticstegby-step operation of the switch until it fin an idle trunk-line. Prior to my invention it was customary to use for this purpose on urrangement involving an interrupter which was common to all of the trunk-selecting switches in the exchange; With such arrangement a. great deal of difiiculty was expenenced-as, for example, should the mach v anism of such interrupter get out of order it is obvious that the whole exchange would then be temporarily rendered ino erative. With my improved arrangement owever, each selector or trunk-selecting switch has its own intcrrupter, and we, the exchange ,apparatus is no longersu jcct to a. single a'ndmo're or less complicatedintpb' rupting-machine. lnothervwords Lprovido so ectors or trunk-selecting swi smechanisms having individual interruptcrs whereby each interrupter when it becomes mjuredor rendered unfit for use. does not thereby render the entirc cxc first. selectorisullot toeach subscriber's line; there is than with my'irhprovqdnb' rangement an: individual. automatic unborruptcr for each line. any event; however, I rofcr' the l arrangement by which the switcheswhich pa'r'forn operations corresponding to the digits of. any called number have individual interrupters, and, as stated, one of the most important features of my invention consists in ruptcrs for different switches or for difierent parts of the exchange apparatus whereby the failure of one interrupterwill a.t .least not render the entire exchange inoperative.

As I am the 'first to succcssfull ylgarp and employ a current-interruptorw is operste directly by a telephone trunk-selecting switch mechanism so as to produce an intermittent .o'r interrupted current as e inoperativegh If.

the use of' inter;

longs/s busy trunks areencountered, it is obvious that more or less c e or variation can be made in the construction without doarting from the spirit of my invention; and or this reason I do not, as far as tho broader aspect of my invention is concerned, limit myselfto thcoxact construction shown and described. H y

I claim as my inventionl i 1. Incombinati u with trunk-lines, a telephone trunk-selecting apparatuscompriaing ste by-step mechanism; an energrating-circuit for effecting the operatiqnlof.

said stepfiiy-stopmechamsm, switch-contacts l in 'saidcircuit, and a. magnet also in'said ci1:-

mg current for the purpose ol mninlnining a 1 cult, and with means whereby said contacts are alternately opened and closed by the altcrnatc energizing and deenergizing of said magnet to ether with automatic means adapted and operative to maintain the vibratory or intermittent energization of said magnet until an idle trunk-line is found, and means for supplying all necessary energizingcurrent.

22. In combination wit trunk-lines, a telephone trunk-selecting apparatus comprising an eleetromagnet, an energizing'circuit for said magnet, normally closed contacts in said circuit, means operated by said magnet for alternately opening and closing said contacts, and step-by-step mechanism operated by the alternate make-and-break action produced by said magnet in its own circuit together with automatic means adapted and operative to maintain the vibratory or intermittent energization of said magnet until an idle trunk-line. is found, and means for supplying all necessary energizing-current.

3. In'combination with trunk-lines, a telephone trunk-sclecting apparatus comprising an electromagnet, an energizing-circuit for said magnet, means for closing said'circuitQ means operated by said magnet for alternately opening and closing its own circuit, and stcp-bystep mechanism dependent for its operation upon the makc-and-break action produced by said magnet in its own circuit together with automatic means adapted and operative to llltlitlitlilltlll vibratory or intermittent energization of said-magnet unti] an idle trunk-line is found, and means for supplying all necessary encrgizing-current.

4. in combination with trunk-lines, a telephone trunk-selecting apparatus comprising a rotatable switch-shaft, an electromagnet, an energizing-circuit for said magnet. switching means operated by said magnet for alternately opening and closing its own circuit. and a pawl'and-ratehet device for rotating said shaft and dependent for its continued operation upon the make-altd-break action produced by-said magnet in its own circuit together with automatic means adnplcdand operative to maintain the vibratory or intermittent encrgization'of said magnet until an idle trunk-line is found, and means for supplying all necessary encr iZing-current.

5. In combination with trunk-lines. a telephone trunlcsolec'ing apparatus complising an electromagm-t, a rotatable switch-shaft, a pawl-aml-ratchet device for rotating said shaft in a step-by-ste manner, means act itated by said magnet or operating said pawl and-ratchet device, an energiziltg-c-trcnit for said magnct and means also actuated in said magnet for alternately opening and e using its owncircuit together with automatic means adapted and operative to maintain the vibratory or intermit tent energization of said magnet until an idle trunk-line is found, and

means for supplying all necessary energizingcurrent.

6. In combination with trunk-lines, a teleplume trunk-selecting apparatus comprising a step-by-step switching mechanism, an electromagnet for actuating said mechanism, a normally open energizing-circuit for said magnet, electromagnetic means for closing said circuit, and means 0 )erated by and adapted to open said circuit w 1911 the said electronmqnet is energized together with automatic means adapted and operative to maintain the vibratory or intermittent energization of said magnet until an idle trunk-line is found, and means for supplying all necessary energizin current.

7. In combination with trunk-lines, a telephone trunk-selecting apparatus comprising a selector" for automatic telephone systems, comprising a step-by-step switching mechanism, and means for automatically continuing the operation of said step-b v-step mechanism until the desired result is obtained, said means including an electromagnet, an energizing-circuit for said magnet, and means operated by said magnet for alternately opening and closing its own circuit together with automatic means adapted and operative to maintain the vibratory or intermittent energization of said magnet until an idle trunk-line is found, and means for sup plying all necessary ener izing-current.

H. In combination with trunk-lines, a telephone trunk-selecting apparatus comprising an ant omatic selective step-by-step switching device comprising a step-by-stcp mechanism, and means for automatically maintaining the stcp-by-step mechanism in operation until the desired result is obtained, said means including an electromagnet, an energizing-circuit for said magnet, and means operated by said magnet for alternately opening and closing its own circuit together with automatic means adapted and operativeto maintain the vibratocv or intermittent energization of said nmgnct until an idle.trunk-line is found, and means for supplying all necessary energizingcurrent.

9. In combination with trunk-lines, a telephone trunk-selecting apparatus comprising an automatic selective step-by-step switching mechanism comprising a step-by-step mechnnism. aml means for automatically maintaining the step-by-stcp mechanism in operation until the desired result is obtained, said means including anelect romagnet, anormally open energizing-oircuit for said magnet, and means operated by said magnet for alternately opening and closing its own circuit together with automatic means adapted and operative to maintain the vibratot'y or intermittent encrgization of said magnet until an idle trunk-line is found. and means for supplying all necessary energizing-current.

as ore 10. In combination with trunk-lines, a telephone trufik-selecting apparatus com rising a rotatable switch-shaft, a ratchet-w eel on said shaft, a pawl for engaging saidratchet to rotate the shaft in a stepby-st ep manner, an electromagnet, an armature for said magnet, said armature being connected to operate said pawl, an energizing-circuit for said ma net, normally closed switch-springs included in said circuit, and an interrupter-arm connected to said armature and adapted, upon the energizing of said magnet, to separate said springs and then, upon the consequent deenergizing of said magnet, keep said springs out of contact with each other until t e armature is restored to its normal position together with automatic means adapted and operative to maintain the vibratory or intermittent energization of said magnet until an idle trunk-line is found, and means for supplying all necessary ener icing-current;

11. The combination step-by-step switching mechanism, an energizing-circuit for effecting the operation of said ste -bystep mechanism, switch-contactsin sai "c1r cuit, and a magnet also in said circuit, together with means whereb said contacts are alternately opened and cl dsed by the alternate energizing and deenergizing of saidma net, there being a suitable structural PIOVI- sio for effecting a positive interruption of' ca step of the mechanical step-by-step motion (produced by the alternate ener 'zing and eenergizing of said magnet, an the said magnet operated circult controlling means being adapted and timed in its opera tion to maintain the continuit of the circuit until after the armature 02 said magnet reaches the limit of its propulsive stroke, whereby the positive interruption of the mechanical motion takes place each time just prior to the automatic opening of said circuit.

12. The combination of an electromagnet, an ene 'zing-circuit for said magnet, normally c osed contacts in said circuit, means operated b said magnet for alternately opening an closing said contacts, and step-' byestep mechanism operated by the alter said magnet inits own circuit, there being a suitable structural provision for efiectmg a positive interruption of each step of the Inc-- chanical step-by-step motion produced by the alternate energizing and energizing of said magnet, and the said magnet-operated circuitcontrolling means being adapted and nate .make-and-break action, produced byenergizing of said magnet, and the an ehergizing-circuitfor said magnet, nmnns for closing said circuit, means operated said magnet for alternately opening and cl 2- ing its own circuit, andstep-by-step mechanism dependent for its operation u on the make-and-break action produced W said magnet in its own. circuit, there being a suittive interruption of each stop of the mcc anical step-by-step motion reduced by the alternate energizing and (energizing of said magnet, and the said inaguet-opcrated circuitcontrolling means being adapted and timed in its operation to maintain the continuity of the circuit until after the armature of. said magnet reaches the limit of its propulsive stroke, whereby the positive interruption of the mechanical motion takes place each time just prior to the automatic opening of said circuit.

,14. The combination of arotatable swihzhshaft van electromagnet', an energizingcircuit f or said'magiet, switching means operated by said magnet for alternately opening and closing its myn circuit, and a pawl-"andratch'et device for rotating said shaft and de pendent for itscontinued operation upon the make-and-break action produced by said magnet inlits own circuit, there being a suitable structural provision for eiiecting a ositive interruption of each step of the mec anical step by step motion reduced by the alternate energizing and (.eonergizing of said".

wit-controlling means bei a apted and timed in its operation t maintain the continuit of the circuit until after the armature 'of said magnet reaches the limit of its propulsive stroke, whereby the ositive interruption of the mechanical motion takes place each time just prior to the automatic opening of said circuit. 1

15. The combination of an electromagnet, a rotatabie switch-shaft, a pawl-and-ratchet device forrotating step manner, means actiiatcd by said magnet for operating said awl-and-ratchet device, an energizing-circuit for said magnet, and means also actuated by said magnet for alternately opening illd. closing its own circuit, there being a suitable structural provisionfor efl'ecting a positive-interruption of each step of the mech anieal step-by-step motion produced by the alternate energizing and des gnet-operated circuit-controlljngmeans ,being adapted and timed in its operation to maintain the continuity of the circuit-until after the armature of said ma et reaches the limit of its propulsive stro e, whereb the tion takes place each time just prior to t-hei l automatic opening of said circuit; 5 16. The combination" of a Step-by-steP switching mechanism, on electnomaghet said shaft in. a step-byable structural provision for effecting a I osimagnet, and the said magnet-o erated cirs 10C positive interruption of, the nicchanica fine-.-

actuating said mechanism, a normally open energizing-circuit for said ma 'net, electromagnetic means for closing said circuit, and means operated by and adapted to open said circuit when the said electromagnct is energ'zed, there being a suitable structural pro continuing the o ration ofsaid step-by-step mechanism une the desired result is ohtained,'said means includin an electromagnet. an energizing-circuit or said magnet, and means operated by said magnet for alternately opening and closing its own circuit, there being a suitable structural provision for effecting a sitive interruption of each step of the .mee anical step-by-step motion produced by the alternate energizing and denergizing of said magnet, and the said ma 'net-' operated circuit -eontrolling means eing adapted andtirned in its operation to maintain the continuity ofithe circuituntil after the armature ofsanl-magnct reaches the limit of its propulsive stroke, whereby the positive interruption of the mechanical motion takes place each timd just-T'prior to the automaticopenin of said eirc'nit.

18. u an automatic telephone apparatu an automatic selective stepb \'step switching device comprising a step-by-step llltt'llflllism, and means for automalirallv maintaining the step-b v-step mechanism in opera! ion until the desired result is obtained, said m ans including an clcel-romagnet, an energizing-rircuit for said magnet and means operated by said magnet for alternately opening and closingils o\\'n circuit, there being at suitable structural provision l'oreil't-rling a positive interruption of each step of the me- ;ehanivul step-by-stop motion produced by Q the alternate energizing and ill-energizing of Q5 said magnet, and th said lnngmbupernlml circuit-controlling means being adapted and t.imqd in its operatipn to mainlain the continuity ol' the circuit until after the armnl ore of said magnet reaches the limit of its propulsive Sll'0 l,'\\l\l'l(lI V the positive interruption of the mer-l'i tnicul motion takes phu-e var-b tim just. prior to the :mlomalivopi-ning "and the =||rl i'ongm-l-opernlrd ('ll'tllll-(llll ol aid ir uit.

I". in an :tuloumllc telephone apparatus.

. -5 an zlutdtn ati Selective sH-p-by-sh-p switch- .dnced by the alternate energizing and deiincrgizing of said magnet, and the said nmgnetoperated circuit controlling means being adapted and timed in its operation o maintain the continuitr of the circuit until after the armature of said magnet reaches the limit of its propulsive stroke, u'hereln' the positive interruption of the mechanical mot-ion takes place each time just prior to the automatic opening of said circuit.

'20. An automatic tele )hone-switch comprising a rotatable swite i-shaft, a ratchet- \rheel on said;shaft, a pawl for engaging sal ratchet to rotate theshaft in a step-by-step o manner, an eleetromagnet, air armature for said magnet, said armature being connected to operate said pawl, an energizing-circuit for said ma net. normally closed switch-springs inclnded in said circuit, and an interrupter- '95 arm eomiected to said armature and adapted, upon the energizing of said magnet, to 'sepa-. rate said springs and then. upon the consequent deenergizing of said magnet, to keep said springs out of contact with each other until the armature is restored to its normal position, there being a suit able st rnrtural provision for ell'erling a positive interruption of each step ol" the meellaniral step-by-stcn motion produced by the alternate energizing (05 and deencrgizing of said magnet, and the said mngln'l -oper=ued i-irirnit-rontrolling means being adapted and timed in its operation to maintain the vulIllHllll-y of lhe rlrruit nnl-il ailerthe tllllltlllll't'fll said magnet rearheslhe no limit f its propulsive stroke, whereby the positive interruption of the nirrhanirnl motion lakes phu-e ran-h time jusl prior to the automatic opening of said rirrnil.

ll. 'lho combination ul step-lrv-step H5 switching mechanism. an em-rgizing-cirmlIt lot oll'erting the operation of said step-b)- sti-p uwrhanisln, sn'ih'h-rontm'ts in said-(1rr-oit. and a magnet also in snitl eireniLi-ogetln-r with means whereby said cont-nets are nllvln:llvl opened and rlusml by the nllernalt energizing and deiun'rgizingol said magm-l. there being a suitable structural provision for ell'eeling a positive interrupthan of oar-h step of the nu-rhanical slrpr25 ivy-slop motion Pl'utlllr'ml h the alternate energizing :unl di-f-uergizing of said magnet.

trolling means being mlnpled and timed in its opt-ration to mainta n the nm-essanv (ull- I30 magnet in its own circuit, there being asuitable structural provision for cfi'ectmg a ostive interruption of each step of the mec anical step-by-step motion produced by the alternate energizing and deenergizing of said magnet, and the said magnet-operated cirwit-controlling means 'belng adapted and timed inits operation to maintain the necessary condition of the circuit until after eacli step of the motion is completed, whereby the positive interruption of the mechanical motion takes place each-time just prior to the automatic change of conditions in said circuit.

23. The con'ibination'with an electromagnet, an energizing-circuit for said magnet, means for closing said circuit, means operated by said magnet for alternately opening 7 and closing its own circuit, and stepby-step magnet, an

mechanism de endent for its operation upon themake-andreak action reduced by said magnet in its own circuit, t iere being a suitable structural provision for efl'ecting a posi-' tive interruption of each'step of the mechanical step-by-stcp motion rodueed by the al-' energizing of said the said magnet-operated 'circult-controlling means being .adapted and timed in its operation to maintain the necessary condition of the circuit until after each step of the motion is completed, whereby the terna te eneggizmg and positive interruption of the mechanical mo tion takes lace each time just prior to the automaticc iange of conditions insaid circuit.

24. The combination of a rotatable switchshaft, an electromagnet, an energizing-circuit for said magnet, switching means operated by said magnet for alternately opening and closing its own circuit, and a pawl-andratch i device for rotating said shaft and dependent for its continued operation upon the make-and-ln'cak action produced by said magnet 'in its own circuit,tliere being a suit,-

able structural provisionfor eil'ectinga ositivc interruption of each step of the nice lanical step-by-step motion iroduced by the alternate energizing and (ecnergizing of said magnet, and the said magnet-operated circult-controlling means being ads )ted and timed in its operation to maintain t is necessary condition of the circuit until after each step of the motion is cmnpleted, whereby the positive interruption of the mechanical incl! 6} tion takes place each time just priorto the automatic change of COXMlIiIODS in said circuit.

25. The combination of an elcctron agnet, a rotatable switch-shaft. a pawl-and-ratchet device for rotating said shaft in a step-bystep manner, means actuated by said'inagnet for operating said awl-and-ratchet device, an cner izing-circuit for said magnet, and means 'a so actuated by said magnet for alternately opening and closing its own circuit,

there being a suitable structural provision for efi'ectinga positive interruption of each step of the mechanical step-by-step motion produced by the alternate energizing and deenergizing of said magnet, and the said magnet-operated circuit-controlling means being adapted and timed in its operation to maintain the necessary condition of the circuit until after each step of the motion is com leted, whereby the positive interruption of t 6 mechanical motion takes place each time just prior to the automatic change of condit ons in said circuit.

26. The combination of a stepby-step switching mechanism, an electroina net for actuatmg said mechanism, a norma y open energizing-circuit for said ma net, electro.

magnetic means for closing said circuit, andf means operated by and adapted to open said circuit when the said electromagnet is energized, there being a suitable structural provision for effecting a positive interruption of each step of the mechanical step-by-stcp m6-, 5

tion produced by the alternate i'ncrgizin and denergizing of said magnet, and the sail magne t-opcrated circuit-controlling means being adapted and timed in its operation to 1 maintain the necessary condition of the circuit until after each step of ihe motion completed, whereby the positive interruption of the mechanical motion takes place of conditions in said circuit.

27. A selector for automatid telephone each time just prior to the automatic change,

systems, comprising a step-by-step switdhing mechanism, and means for automatically continuing the o eration of said ste -b'y-step mechanism nut] and means operated by said magnet for alternately opening and closing its own circuit,

there be ng a suitable structural provision for effecting a ositive interruption of each step.

of the mec anical step-by-step motion produced by the alternate energizing and denergizing of said magnet, andthe said magnetoperated circuit-controlling means being adapted and timed in its operation to maintain the necessary condition of the circuit until after each step of the motion is com leled, whereby the positive interruption of t e Incthe'desired resu t is" ob taine'd, said means includin an electromag-- J15 net, an energizing-circuit or said magnet,

chanical motion takes place each time just prior to the automatic change of conditions in said circuit.

28. In an automatic telephone apparatus, an automatic selective step-b -step switching device comprising a stepii -step mechamsm, and means for automatically maintaining the stepbystep mechanism in operation until the desired result is obtained, said means including an electromagnet, an energizing-circuit for said magnet, and means operated by said magnet for alternately opening and closing its own circuit, there being a suitable structural provision for effecting a positive interruption of each step of the mechanieal step-by-step motion produced by the alternate energizing and deenergizing of said magnet, and the said magnet-operated circuit-controlling means being ada ted and timed in its operation to maintain t 10 necessary condition of the circuit until after each step of the motion is completed, whereby the positive interruption of the mechanical motion takes place each time just prior to the automatic change of conditions in said circuit.

29. In an automatic telephone apparatus, an automatic selective step-by-step switching mechanism comprising a step-by-step mechanism, and means for automatically maintaining the step-by-step mechanism in operation until the desired result is obtained, said means including an electromagnet, a normally 0 en energizing-circuit for said inagnet, an means operated by said magnet for alternately opening and (losing its own circuit, there being a suitable structural provision for effecting a iositive interruption of each step of the mechanical step-l y-step motion produced by the alternate energizing and deinergizingof said magnet, and the said magnet-operated circuit-controlling means being adapted and timed in its operation to maintain the necessary condition of the circuit until after each Step of the motion is completed, whereby the positive interruption of the mechanical motion takes )lace each time just prior to the automatic c iange of conditions in said circuit 30. An automatic telephone-switch comprising a rotatable switch-shaft, a ratchetwheel on said shaft, a pawl for engaging said ratchet to rotate the shaft in a step-by-stcp manner, an electromagnet, an armature for said magnet, said armature being connected to operate said pawl, an QHQIgIZIIIQ'CIIL'UIL for i said magnet, normally closed switch-springs included in said circuit, and an interrupterarm connected to said armature and adapted, upon the energizing of said magnet, to separate said springs and then, upon theconse quent denergizing of said magnet, keep said springs out ofcontact with each other until the armature is restored to its normal position, there being a suitable structural provision for effecting a positive interruption of each step ofthe mec anical step-byI-step motion produced by 'the'alternate energizing and deenergizing of said magnet, and the said magnetoperated circuit-controlling means being adapted and timed in its operation to maintain the necessary condition of the circuit until after each step of the motion is com leted,

whereby the positive interruption of t 1e mechanical motion takes place each'time just prior to the automatic change of conditions in said circuit.

' 31. The combination of step-by-step switching mechanism, an energizingscircuit for effecting the operation of said' ste bystep mechanism, switch-contacts in sai circuit, and a magnet also in said circuit, together with means whereby said contacts are alternately opened and closed by the alternate energizing and denergizing of said magnet, said magnet-operatedcircuit controlling means being adapted and timed initsoperation to each time maintain the necessary condition of the circuituntil after-the armature of said magnet regains its normal position,

whereby the said armature always reaches its position of rest just prior to the" automatic change of conditions in the said circuit.

32. The'combination of an electromagnet, an energizing-circuit for said magnet, normally closed contacts in said circuit, means operated by said magnet for alternately opening and closing said contacts, and Step by-step mechanism operatedbythe alter ing its own circuit, and step-by-step meehanism dependent for its operation u on the makc-and-break act on produced W said magnet 111 its own clrcuit, said magnet-opera ted circuit-controlling means being adapted and timed in its operation to each time maintain the necessary condition'of the circuit until after the armature of said magnet regains its normal position, whereby the said armature always reaches its osition of rest just prior to the automatic c ange of conditiops in the said circuit.

34, The combination of a rotatable switchshaft, an electromagnet, an energizing-circuit for said magnet, switching means operated by said magnet for alternately opening and closing its own circuit, and apawl-andi o" :irilistureqi liinys 4 1- i U .0 site. no trely open ng and closing its own on ratchet device for rotating said shaft and de pendent for itscontiiiued operation upon the nmkc-und-hieuk action produced by said inngnctii'ti'tS own circuit, said magnet-oper- -a ted ('-lI'C11l'h-C()nhIUlllllg moans living adapted and timed in itsoperiition to l(il time maintain-tho? iier'ossiirv (fOIk li lOH ol' the circuit Hfitll-liiillf.t llttilllllililll'fl of said mii n'ct rcgains itsnormul position, \rhoreh v ilic said reaches its iosit-ion of rest just pizior to the automatic change of conditions in the siiiilrircuit.

35. Tl e coinliiniitiunj of an electroinagnet, a i'iitiitu'lilc switclisliu.ft,apu'u l-iind-ratcliet *doi ice I 'rir'iti ti-ng said shiift in a step-bystei i nninnoi", incnns actuated by said [Hagnot Tor 'iipori tii'i said piiwl-n-nd i'ii tchet device, 11 n energiz rig-circuit for said magnet, and inen'i s also sctiiated by said, magnet for rirfifljsqid magnet-operated circuit-controlling means hei'n adapted and timed in its opqigii'tiqn to, cite 1' time niiiintain tlie necessary condition of thcircu'it until after the adopted and timeu in its operation to time maintain the necessary condition of the .ing mechanism comprising arniaturel-.of said-magnet regains its normal position, whereby the said .armature alwavs reag'l' g -s itSJwSitlgm of test just prior to the iiu'wui'uticelinnge of conditions-in the said 3'61 fIJie coiiihi ation of V a stp-by-stcp swjtchiiifi meclu nisni, 'aii electromii net for iii-.tuiitingsuid inecluuiism, a norms ly open eneigiziug-circiiitfifor said inagiict, electrounig'n'etic iiiii iinslor closing said circuit, and iueir ik operated. l yn u'l adapted to open said rircjuit wlj'eli the said electroinagnct is energiz'ed, said .in"gum-operated circuit-controlling means "heing'ndapted and timed in its opeiiitio'ri to each time maintain the necessiirf 'l'oniiitiiui of the circuit until after the :LllllaiilllO of siiizl iniignet regains its normal position, whervl v the said armature alwavs reaches its lmsition of rest just priorto the iilitr'ni utic clninge of connitioiis in the said circuit.

37. A selector for automatic telephone systems, comprisingii step-liy-step switching nu-eliauism. and means for automatically continuing the operation of said she Jivstop mechanism until the desired result is ohtnincd, said means including an electromagnet, an ei'i-orgizing-circuit for said magnet. and,v niezinsoperuted hy said nnignet for alter-- mliA l V opening and olosing'its own circuit, said magiiet-opcrii ted circuit-controlling iueu'iis heing':idifi ited and timed in its operation to each time 'umiutaiii the necessary conditioii of the circuit until-after the armature of said ;lll iillil regains its nornml'position, \\'llll'(ll}' the said armature always reach-sits pusilinll of rest just prior to the automatic rhuuge of (fuliiiitiuus in the said circuit.

Ila. in an iiutonnilic telephone apparatus,

anism, and means for automatically main- -step mechanism m opertnining the step-l v ution until the desired result isobtaiiied, said means including an electroiuiignet, an energizmg-circuit for said magnet, and means opemted by said magnet for alternately opening and closing its own circuit, said magnetopcrsted circuit-controlling means being circuit until after the armature of said mag:

net regains its normal position, whereby the' each sai-l armature always reaches its position of rest just prior to the automatic change of conditions in the said circuit.

39. In an automatic telephone apparatus,

in automatic selective step-by-step switchmechanism,

said means including, an 'electromagnet, a normally 0 en energiznigcircuit for: sa d a 'step-by-si p, ii and means for automatically W maintaining the ste -by-step'mechanisnri rl operation until the esire'cl result is obtained magnet, an means operated by said magnet .for alternately opening and closing its own circuit, said et-operated circuit-com trolling 40. The combination of step -'by-step means being ,adapted and timed iu'its operation to each time maintain the neoe ssary condition of the circuit until after. the armature ofsaid mii-gnet'regains'its normal osition of rest jug! pdontqt ange of conditionsmthe said cirswitching mechanism, on energizingrcircuit' Y for effecting the operation of said step-by step mechanism, switohecontacts in said 'c1r{ cuit, and a magnet also in-said circuit,

gether with means whereby salid'contacts are opened and closed by the alteralternately v nate energizing and denergizing of said net, said ling means bein a apted and timed in its operation to cac ture. of said ma net regains its normal position and until a by the said armaturea we s reaches its position of rest ust ing of said circui 41. The'combination of-anelccti'omugnet, i

an ener izing-circuit for said magnet, norcontacts in said5c-ircuit, means i said magnet for alternately,

opening an closing said contacts, and step (-iiit until after the-armature of saidinagnet regains its normal position, and unlil after time maintain the open condition of the circuit'until after the 'annaprior to t 1e automatic closmagnet-o erated circuit-conti ifi-l ter the said armatureresches the-limit of its non-pro ulsive stroke, where'- 1 the said armature reaches the limit of its nonpropulsive stroke, whereby the said armature always reaches its-position of rest just prior to the automatic closing of said circuit.

42. The combination of an elcctromagnet, an energizing-circuit for said magnet, means for closing said circuit, means operated by said magnet for alternately opening and clos ing its own circuit, and step-by-stcp mechanism dc endent for its operation upon the make-an break action produced by said magnet in its own circuit, said magnet-operatcdcircuit-controlling means being adapted and timed -in its operation to each time maintain the open condition of the circuit until after the armature of said magnet regains its normal position, and until after the said armature reaches the limit of its nonpropulsive'strokc, whereby the said armature alwa s reaches its osition of rest just prior to t c automatic c osing of said circuit. 43. The combination ol'a rotatable switchhhaft, an electromagnet," an energizing-cireuit for said magnet,swit ching means operated by said magnet for alternately opening and closing'its own circuit, and a pawl-andratohetilevice for rotating said shaft and dependent for its continued operation upon the make-anii br'eak action produced by said magnet in'its oivn circuit, said magnet-operated circuit-controlling means being adapt- T ed and timed initsloperation to each time maintain the open condition of the circuit until aftertl e" armature of said magnet regains its normal" position, and until after the said ar'matiircTeat-hesthe limit of its non,- propulsiire stroke, wherc bythe saidarmature always ra'ch'esits position of rest just prior to the automatic closing of said circuit.

44. Thecombination of an electroma net-,a rotatableswitch-shaft,apawl-and-ratc etdevice for rotatingsaid shaft in a step-by-step manner, means actuated by said magnet for operating said pawl and-ratchct device, an energizing-circuitffor said magnet, and means also actuated by's'aid magnet for alternately opening and closing its own circuit, said mag net-operated circuit-controlling means being adapted and timed in its operation to one time maintain the open condition of the circuit until after the armature of said magnet regains its normal position, and until after the said armature reaches the limit of its nonpropulsive stroke, whereby the said armature always reaches its position of rest just prior to the automaticclosing of said circuit, 45. The combination of 'a step-by-stcp switching mechanism, an electromaiznet for actuating said mechanism, a norma ly open energizing-circuit for said magnet, electromagnetic means for closing said circuit, and means operated by and adapted to open said circuit when the said electromagnet is energized, said magnet-operated circuit-controling means being adapted andtnned in its 'magnet, an energizing-circuit or said magbeing adapted and timed in its operation to each time maintain the open condition of the circuit until after the armature of said magnet regains its normal position, and until after the said armature reaches the limit of its non-propulsive stroke, whereby the said armature always reachesits position of rest just prior to the automatic closing of said circuit.

46. A selector for automatic telephone systems, comprising a step-b -step switching mechanism, and means or automatio-, ally continuing the operation of said step,-

by-step mechanism until the desired result 13 1 obtained, said means includin net, and means operated by said magnet for an electro- I 8o alternately opening and closing its own circuit, said magnet-operated clrcuit-controll ling means bein adapted and timed in its operation to eac 1 time maintain the open" condition of the circuit until after the arms-i ture of said magnet regains its normal 1 tion and until after the said armature reaches the limit of its non-pro uls'rve stroke,*' wher by the said armature a we 6 reaches its posi tion of rest just prior to t ing of said circuit. y

47. In an automatic telephone? iiaratu's,

an automatic selective step-b ste 'svfitchwp ing device comprising a stepy-step mech-' anism, and means for automatically'fm 'un taining the step-by-step mechanism ate eration until the desired result is obtained} said" means including an elcctr0inagnet,arf ener-j, gizing-circuit for said magnet," nil" means Operated y 'Said magnet for alternately g opening a osing its own circuit,'said f magnet-operated circuit-controlling means operation to each time maintain the open cont tion' 6f the f circuit until after the armature of said magnet re ains its normal position, and until after t e said armature reaches the limit of its non-propulsive stroke, whereby the said armature a ways reaches its position of rest just prior to the automatic closing of said circuit.

48. In an automatic telephone apparatus, an automatic selective stepby-step switching mechanism comprising a step-by-step mechanism, and means for automatically e automatic clos maintaining the step-bv-stepmechanismin operation until the desired result is obtamed, said means including an ele'ctro:

-magnet, a normally open energizing-circuit for said magnet, and means operate b said magnet for alternately opening and c osing its own circuit, said magnet-operated cirwit-controlling means being adapted and timed in its 0 ration to each time maintain the open con ition of the circuit until after the armature of said magnet regains its normal position, and until after the said armature reaches the limit of its non-propulsive stroke, whereby the said armature always reaches its position of rest just prior to the automatic closing of said circuit.

49. The combination of stepby-step switching mechanism, an energizing-circuit for eli'ecting the operation of said step-bystep mechanism, switch-contacts in said circuit, and a magnet also in said circuit, togethern ith means whereby said contacts are alternately opened and closed by the alter nate energizing and denergizing of said magnet, and the saidmagnet-operated circuit-breaking means comprising an arm ri id with the armature of said magnet, norma ly closed switch-springs, and aifintermediatc spring,saii.l ari n having its end portion adapt.- ed to bear upon the end portion of one switch-spring, when the magnet is energized, and to, thereby flex all three springsybpt adapted'to slip ofi'from such spring just-as the hrmature reaches the limit of its p'ropuL sive stroke," and adapted to then be engaged by said intermediate spring for the purpose of opening or separating said switch-springs, the circuit through the, magnet being thus held closed until after the armature reaches its osi'tion of rest, and the said end portion of t e arm being adapted to'pass between the said intennedia'te s ring and the end portion of the same switci-spring when the armaturennovcs back to its normal position, the circuit being thus held open until after-the armature reaches its position of rest.

50. The combination of an electromagnet,

an energizing-circuit for said magnet, "nor mally closed contacts in said circuit, means operated by said magnet for alternately opening and closing said contacts, and stepi-r-step mechanism operated by the alternate make-and-brcak action produced by said magnet in its owncircuit, and the said magnet-operated eircuit-breakin'g means comprising an arm rigid with the armature of said magnet, normally closed switch-s rings, and an intermediate spring, said arm iiaving its end portion adapted to bear'upon t-he'end portion of one switch-spring'when the mag net is energized, and to thereby flex all three springs, but adapted to slip off from such spring just as the armature reaches the limit of its propulsive stroke, and adapted to then be engaged by said intermediate spring for I the purpose of opening or separating said switch-springs, the circuit through the mag-. net being thus held closed ,until after the armature reaches its position of rest, and the said end portion of the arm being adapted to pass between the said intermediate spring and the end portion of the same switchspring when the armature moves back to its normal position, the circuit being thus held open until after the armature "reaches its position of rest. it

51. Thecombination of an electromagnet, an energizing-circuit for said magnet, means for closingsaid,circuit, means operated by its end portion adapted to portion of one switch-sprin pass 1 between; the said said magnet for alternately opening and closing its own circuit, andstepby-step mechanism dependent for its operation upon the make-andbreak action produced by said magnet in its own circuit, and the said magnet-operated circuit-breaking means comprising an arm rigid with the armature of said magnet, normally closed switch-s rings, and an intermediate sprin said arm avin 516M: upon the en when the magnet is energized, and to thereby fiezgc all three springs, but adapted to slip off from such spring just as the armature reaches the limit of its propulsive stroke, and adapted to then be engaged by said intermediate spring for the purpose of opening or separating said switch-springs, the circuit through the magnot being thus held closed until after the armature reaches its position of'rest, and the said end portion of the arm being adapted to intermediate spring 'and the end portion of the-same switchspring when the armaturemoves back to its normal position, the circuit being thuslheld sltion of rest. v 52. The combination of a rotatable switohshaft, an electromagnet, an energizing-circuit for said magnet, switching means-operated by said magnet for alternately op and closing its own circuit, and a-pawl-an ratchet device for rotating said shaft and dependent for'its continued operation upon the make-and-break action produced by said magnet in its own circuit, and the said mag. net-operated circuit-breaking mea ioomprising an arm rigid with the armature of.

said magnet, normally closed switch-B rings, and an intermediate sgringgsaidarm aving its end pnrtion adapts to ear upon the'end portion of one switch-spring, when the magnet is energized and to thereby flex all three springs, but adapted to slip spring just as the armature reaches the limit of its propulsive stroke, and adapted to then he engaged by said intermediate spring for the purpose of opening or separating said switch-springs, the circuit through the Mag not being thus held closed until affierthe armature reaches its osition of rest, and the said end portion of t e arm being adapted to pass between the said intermediate spring and the end portion of the same switch-" spring when the armature moves back to its normal position, the circuit being thus' held open until after the armature reaches is position of rest. r

a 53. The combination of an electromagnet, a rotatable switch-shaft, a pawl-and-ratchet device for rotating said shaft in a step-bystep nmnncr, means actuated by said magnet for operating said pawl and ratchet device, an energizing-circuit for said magnet. and

means also actuated by said magn t, lter: t, v i .l H,-

off from such 90 open until'after the armature reaches its poa t ereby flex all three springs,

nately'opening and closing its own circuit, and the said magnet-operated circuit-breaking means comprising an anm rigid with the armature of said magnet, normally closed switch-springs, and anintermediate spring,- said arm having its end portion adapted to bear upon the end portion of one switchs ring, when the magnet is energized, and to but adapted to slip ofi from-such s ring just as the armature reaches the limit its propulsive stroke, and ada ted to then be engaged by said intermer iate spring for the purpose of opening or separating said switch-springs, the circuit through the magnet being thus held closed until after the armature reaches its position of rest, and the said end portion of the arm being adapted topass between the said intermediate spring and't'he end,portion of the energizing-circuit for said magnet,

i {and the" said magnetpperated circuitsame switch-spring when the armature moves back to its normal position, the circuit being thus held open until after the armature reaches itsposition of rest.

54. The combination of astep-by-step switching mechanism, an electroma net for actuating said mechanism, a norina ly open electromagnetic means for closing said circuit, and means operated by and adapted to open said circuit-when the' said electromagnet is enerreal'nng means comprising an arm rigid with the armature of saidmagnet, normally closed switchsprings, and an intermediate spring, saidar'm'having itsend portionadapted to bear upon the end 'portioniof one switch- 5 ring, when'the magnet is'eiiergized,'and to t ereb' flexall three springs, but'adapted to slip off from such s ring just as the armature reaches the limit edits propulsive stroke, and ada' ted to then be engaged by said'inter m iate spring for the purpose of opening or separating said switch springs, the circuit through the magnet beingthus held closed uptil after the arrii-ature reaches its position 0 being adapted to pass between the said intermediate sp'ringand the end ortion of the same switch spring when e armature moves back to its normal osition, the circuit be thus held open until after the armature reac as its position of rest.

55. A selector for automatic telephone systems, comprising a step-by-step switching mechanism, and means for automatically continuing the o eration of said step'by-step mechanism unti the desired result is obtained, said means includinfg an electromagnet, an energizing-circuit or said magnet, and means operated by said magnet for alternately opening and closing its own circuit, and the said magnet-operated circuit-breaking means comprising an arm rigid with the armature of said magnet, normally closed switch springs,

t ereb .of one switc -spring, whenthe ,ergized, ,and :to flex all three springs,

rest, and the said end portion of the arm moves back to its norms.

and an intermediate spring;' 1 bear upon the end said arm having its end portion adapted to bear upon the end portion of one switchs Jring, when the magnet is energized, and to flex all three springs, but adapted to slip ofi from such s ring just as the armature reaches the limit 0 its propulsive stroke, and adapted to then be engaged by said intermediate' spring for the purpose of openingor separating said switch-springs, the circuit through the magnet being thus held closed until after the armature reaches its position of rest, and the said end portion of the arm being adapted to pass between the said intermediate springand the end portion of the same switch-spring when the armature moves back to its normal osition, the circuit being thus held open unti after the armature reaches its position of rest.

56. In an automatic telephone apparatus, an automaticseleotive step-b -step switching device comprising a step-hy-step mechanism, and means for automatically naintaining the stepeby-step mechanism in operation until the desired resultisobtained, said means including an electromagnet; an energizingcircuit for said magnet, and means operated bly said magnet for alternately opening and c osing its own circuit, and the said magnetoperated-circuit-breaking means com rising an arm rigid with thenrniature of sai magnet, no ally olosediswitchs rings, and an interin mte sprIiig,-aidarm avin its end portion a'da ted to bear upon the e portion magnet is enbut adapted to slip 0 from such spring just as the armature reachesthe limit of its propulsive stroke and add ted to then be engaged by Saidintermediate spring for the purpose of opening or separating said switchsprings, the circuitdahrough the magnet being t us closed until afterthe armature reaches its position of rest and 'the said end portion of t e arm being adapted to ass between the said intermediate spring-an the end portion of the same switch-sp when the armature ition, the circuit bein' thus held open-ant after the armature reac es its position-ofrest.

V 57. In an automatic telephone apparatus, an automatic selective step-by-step switch ing mecha mechanism, and means for automatically maintaining, the ste' by-step mechanism'in operation until the esired result is-obtained,

said, mea ngincluding an electromagnet, it nor- 7 mally npen energiz ng-circuit or said magnet, an means operated by said magnet for alternately opening and closing its own circuit, and the said lat-operated circuitbreaking means comprising an arm rigid with the armature .of said magnet, normally closed switch-springs, and an intermediate s ring,

said arm having its :endportion adap ed to portion of one switchmsm comprising, a 'step-by-step.

"M.- an

:-r 5 hein thus held open unti sprin' when the magnet is energized, and to t iere flex' all three springs, but adapted to slip efi'?irom such spring just as the armature reaches the limit of its propulsive stroke,

f 5 and adapted to then be engaged by said intormediate spring for the purpose of opening "or separating said switch-springs, the circuit through the magnet being thus held closed until altcrthe' armature reaches its position zo'ol' rest, and the saidend portion of the arm [being adapted to pass between the said inter- "mediate spring and the end portion of the 'Csame switch-spring when the armature moves back to its normal iosition, the circuit iafter the armature reac es its position of-rcst.

' 58. The combination of an electromagnet,

' anenergizing-circuit for said electromagnet,

and a normall close'd switch in said circuit I i I "'i-dtogcther with an armature associatedwith I said magnet and connected for operatin said iswitch, the said switch being adapted "'and timed in its eration'to maIDtB-iDthG :contimiity of the circuit until'after the said armature reaches the limit of its movement "toward the said magnet, whe'reby the move- 'inent of said armature ceases just prior'to the utomaticoponing of said circuit and the 6 and automatically energize and den'ergine T itself as long as the said circuit remains j' closed at all siiin'tch.

59. The combination of anelectromagnt, an energizing-circuit for said magnet, an ar- -maturc forsaid magnet, and a switch controlling said circuit and operated by said armature, said switch being adapted and timed in its operation to maintain the neces- 4o sary condition of the said .circuit until after the saidarmatitre reaches the limit of its movement in one direction, whereby the motion of the said armature ceases just rior to the automatic change 'orrevers'al o condi- 4 5 (ions in said circuit, and the said electromagnet is adapted to alternately and automatic ally cncrglwe and decncrgize itself as lon as the said circuit remains closed at all points 01 her than at the said Switch.

(30. The combination of an electromagnet, an energizing-circuit for said magnet, an armature for said magnet, and a switch controlling said circuit and operated by said armature, said switch being ada ted and timed in its operation to maintain t is open condition of said circuit until after the said armature reaches the limit of its stroke or movement away from the magnet, whereby the motion of thc armature ceases just prior to the automatic closin of said circuit.

61. The combination of an electromaguet, an cncrgiZing-circuit for said magnet, an as mature for said magnet, and a. switch conlrollingsuid circuit and operatcd by said ar mature. said switch bring adaptud and timed po ints'other than at-"the said said electromagnet is adapted to a ternatel'y in its operation to maintain the continuity of the said circuit until after the nri'naturc reaches the limit of its motion toward thc magnet, and to preserve the open condition in said circuit until after the said armature reaches-the limit of its movcmont in the opposite direction. V

()2. The combination of an electromaguct provided with an armature, an :.rm rigid with said armature, a couple of normally closed .switch-sprin s, and an intermediate spring, together with an energizing-circuit for said magnet including said switchsprings in series, the end of'sa'rd' arm bcin; adapted to engage one of said switch-springs and hold the same positively together until the armature reaches the limit of it's'iuovcmerit toward the magnet, but adapted to "then sli ofl'from said switch-springarid be engag by said intermediate spring, the said IIItCI'l'IIGdlRtB" ring being adapted when thus, engaged byt iie arpr to hohlzthe-othcr switch-spring out of c'ont'act with the switcla spring engaged by the "arm,r-v vhcrel iy the mo tion of the armature ceases juslnpnor to the separation of saidsvi itoh-springs and the conse uentfopening'of the circuit.

6". The, combinationof an icqtromagnet provided with. an armaturepan arm rigid with said armature, at-pair of' normally closed switch-springs,.an' intermediate spring, and an energizing-"circuit for saidfmagnct including said switch-springs inseriesfsaid arm being-adapted to engage one or said switch-springs and thereby kee the two SWitCl'l-SPl'iIU'S in engagement,- witheach other until the armature reaches the "limit of its movement toward-themagnctjhut the arm being'adap tcd 'to then sli: oil from-the said switch-spring and bc (ii-ringed; by the intermediate spring for the purposii; or permitting the latter to ilklilLVlltlltl thcpthcr switch-spring.- out of 'co11tac.g='.,w itli the switchspring engaged by the art-oi, and a portion of said arm being adaptedzkivhen. tho armatuno is retracted to pass between their:- termediate spring-and the said,switehg pring which-is e 'aged'jby the arinfjnhe rplrwthc motion .of t e armature ceascsijust; pmo'rco the opening of the circuit, and-tire;i ircuit then remains open until after the armature reaches the limit ofjts movement away from the ma netl 64. n a telephone system, the combination of trunk-lines, a bank of terminals for said lines, a trunk-selecting switch mechanism coiiperating with said terminals, and a source of operating-current therefor, together with an operating-circuit for said l'lllllk-Hflh'Ctifig switch mechanism, the said mechanism having an opcratiimgr-electromagnot included in said circuit and providcd with automatic means for intcrmiflcntl} opcuing and closing the said circuit at one IZG . f interrupt the operating currentj for verting the intermittent energization of said magnet into a stepby-step search for an idle trunk-line, and automatic means for maintaining thecontinuity of said circuit at all 5 other points until the idle trunk-line is found.

65.'The combination of a lurality of trunk-lines, terminals for said ines, and a trunk-selecting switch mechanism cooperat- |o with said terminals and having an operst electromagnet provided with auto- 'mat1 c means for intermittently interrupting the flow of o crating-current therein until [an idle trunkine is foundas a resultof the I5 automatic step-.by-st'ep search produced t ereby. it

.66.- n automatic telephone apparatus, a trunk-selecting switch .mechanism; and =an autornatic currentdnterrupter operated by zcg, saidswitch mechanism, adapted to intermitsaid'mechanism to causethc switch to pass busyttrunk-lines, and whereby the switch [8 automatically retained in operation until it In automatic, telephone switching apparatus, the combination of an electricallypropelled andstep-by-step actuated'trun .switch mechanism, andan auto- 3o' xnaticl current-interrupter. individual to said switch jmechanism and operated r thereby, adapted to intermittently interrupt the op'erl ating current -for said mechanism to cause the switch to passbusy trunk-lines, substan- 5 iially as and for thepurpose set-forth. In automatihtelephone apparatus, the combination of a plurality of trunk -lines, an ,automaticgtrunk-selecting switch mechanism therefor, and an automatic-current -intert rupterindividual to'said selectin mechanfi sm and o rated thereby, adapt to intermittently mterrupt the operating-current for saidniechanism to cause the switch to pass busy trunk-lineasubstantially as and for the 45 purpose. set'forth.

. 69 The combination of telephone-trunks, means for selecti an idle trunk, an operatter for sai l circuit, adapted to alternigt.

' search fo'r an idle pr co -means or selecting .thgfi gt ,idle means including a on. antnterrupter ,indi- 'uig magnet for sai means, an energizing-circuit for said ma et, an interrupter. for said circuit, operate by said magnet to. produce an intermittent current-flow therein, and additional means for opening and 'closin said circuit, whereby the flow of interrupte cur-' rent ceases as soon as anjdle trunk. is found:

70. Ina tele hone system, the combination of trunkines, andazitrunliselectin switch mechanism, said r hechanism provide with an electroma et, means operated by said magnet, adap ed to produce a step-bystep search for an idletrunk-Line, an energizing-circui t for said magneLfand, an interrup- 'rgttd bjgisaidl magnet, H eaergizeanddenen gize's'ald lnagnet'to ca ,Itliiqfiylfih tqpass usylmesaiidstopjiin v ifirstl dleline.- 65 '71. In adevice ,ofjthe, class; specified,, the 4 combination er trunks or comgnon (talking i s'lsn t "Elisa t-Wa ted up r'atus for; a'fit' (ally .irnak pg"v a'stepli ail fdltt ,n-aakpr connection, s'ai apparatus" haying a 'step-by-step mechanism provided with an opera'tin -magnet for usemaiaki g the search for an'i le trunk or connection, aden sing-circuit for said magnet, an" interruptei' fo11 said .circuit, individual to saidfipmws, opemtea said magnet, adap f w alternately .open. and close sa d circuit to rodu e the step-by-step ection, and means for li eeping the circuit: osed'and the interrupter in"operation until an idle trunk or connection is selected."

72. The m binati n of ,telephoneelines,

and electric-'curi-ei'it-tiperated' step-by-stqg me, sai

vidua'l theretonnd ada liar vibrating .qr pulsating the operatifii' v u'ent thereof until thefirst idle line is s" acted.

1 Signed by me atChiea 0, Cook county, .90 Illinois, this 7th dayof'Fe wary, 1905.

ALEXANDER KEITH.

Witnesses:

" W; Lee CAMraELL, R. CJGIFFO'RD. 

